This application relates generally to combination locks for lockers.
Combination locks are used to secure or lock the door of lockers, cabinets, toolboxes, desks, and other such enclosures. A low cost solution of such combination locks includes the use of spring bolts that actuate in response to entry of the correct combination. Such spring bolt combination locks eliminate the need for bulky and expensive handle mechanisms.
In many applications, the user of the combination lock changes over time. For instance, lockers in a school are often assigned to one student user for a period of time, such as a school year, and then assigned to another student in a following school year. In this example, the school often times desires to retain the ability to gain entry to the locker without need of the combination. Thus, combination locks are provided with a master key. The master key can actuate the spring bolt to open the lock without the combination. The master key, when used with a push button mechanism, changes the combination of the lock to one of several different pre-assigned combinations.
Examples of such key-controlled combination changing permutation locks are provided in U.S. Pat. Nos. 3,023,600, 3,023,602, 3,031,876, 3,031,877, and 3,190,089 to Foote et al., the contents of which are incorporated herein by reference thereto.
Prior combination locks have several disadvantages for example, prior locks having a fully retractable bolt have a less than desired bolt throw (e.g., not more than about 0.25 inches). Alternately, some prior locks have been made with longer bolt throws, but do not allow for the complete retraction of the bolt. The prior locks also provide a less than desired number of available pre-assigned combinations. Moreover, such combination locks do not avoid unauthorized entry when used in situations where the frame of the locker is capable of being bent outwardly enough to allow the bolt to no longer be engaged in the frame thus allowing the locker to be opened.